Cultivation of some types of crop, for example cotton, may be performed in cultivation rows that essentially follow the contours of the land. When tilling between planting this is desirably performed by reshaping of cultivation rows rather then by generating an entirely new series of rows.
In the past attempts have been made to provide an apparatus which facilitates reshaping of cultivation rows. For example, in U.S. Pat. No. 5,941,317 to Mansur there is described a row cultivator including a fixed toolbar and a trailing moveable toolbar. Lateral displacement of the moveable toolbar relative to the fixed toolbar is facilitated by an actuator. A pair of mechanical sensors located on opposing ends of the trailing toolbar each determine the position of adjacent, pre-existing, furors. A mechanical apparatus is responsive to the sensors and generates a difference signal that is used to control the actuator in order to reduce furrow spacing irregularities as the row cultivator is passed over the pre-existing furrows.
A problem with the prior art approach to reshaping the furrows is that the reshaping is partly a function of the position of the pre-existing furrows. Accordingly a calibration error in the apparatus may cause error to accumulate so that over a number of seasons the re-shaped furrows become more, rather then less, irregular.
In addition, the practical limits imposed by wheelbase, steering scrub, towing pull and traction of the propulsion unit will necessarily limit the precision at which the cultivator may track the desired cultivation path.